From: Dace (edace@earthlink.net)
Date: Thu 19 Jun 2003 - 19:54:25 GMT
> From: "Ray Recchia" <rrecchia@mail.clarityconnect.com>
> Subject: Re: Precision of replication
>
> All of this gets back to Manfred Eigen's notion of 'quasi-species' which
> can be identified mathematically using the concept of a multi-dimensional
> fitness landscape. In a fitness landscape, higher points in one
> dimension of the landscape indicate more reproductive success while lower
> points in that dimension indicate lower reproductive success. Offspring
> placed higher at the top of a fitness peak will be more successful than
> those at the bottom. Because variation is constantly occurring, no
> particular member of a species is exactly the same as any other but all
> hover about the same fitness peak. Species then becomes defined by the
> presence of a group of organisms sitting on a slope that is directed
> towards the same local peak.
Very interesting. What intrigues me about Eigen's model is that it's
exactly the opposite of C.H. Waddington's model of development. Waddington
also uses a hill to illustrate his point, except that in this case the goal
is to go down the hill rather than up. Picture a hillside with many grooves
("chreodes") carved into it. If an embryo has gene A, it will take one set
of grooves down the hill, and if it has gene B, it will take a different set
to the bottom, where it will land at a different place, i.e. it will end up
with a different set of characteristics.
It makes perfect sense to envision evolution as an uphill climb while
looking at development as a downhill descent. The reason is that evolution
is a struggle to attain greater fitness in order to be environmentally
selected. Development, on the other hand, is all about following the path
of least resistance. You simply slide down the trail your ancestors blazed
before you. To a limited degree, development is a recapitulation of
evolution, except that instead of forging a path through struggle over many
generations, an embryo merely follows the path already laid out. Evolution
is all about creativity (the true "creationism"), while development is all
about following ingrained habit. Individuals can be regarded as belonging
to a common species when: 1) they reside on slopes directed to a common
fitness peak and 2) their offspring descend through a common developmental
pathway.
Culture involves the same dual process. On the one hand, we create and
promote ideas based on their fitness. On the other hand, when an idea is
repeated enough, it becomes habitual, and our thinking merely follows the
synaptic patterns already laid out for it. When a habitual pattern of
thought is transmitted and becomes a culturally-shared habit, it's a meme.
My point is that "habit" is the missing middle term in memetics. While a
new idea must be consciously reconstituted each time it appears, a habit of
thought takes on a "life of its own" and continues promoting itself long
after its originator has consciously forgotten it. A meme, then, is simply
a habit of thought that replicates across many minds as it becomes
culturally ingrained.
Ted
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